Araucaria (La Mer de sable) cone.jpg

''Araucaria'' (; original pronunciation: .ɾawˈka. ɾja is a genus of evergreen coniferous trees in the family Araucariaceae. While today they are largely confined to the Southern Hemisphere, during the Jurassic and Cretaceous they were distributed globally. There are 20  extant species in New Caledonia (where 14 species are endemic, see New Caledonian ''Araucaria''), Norfolk Island, eastern Australia, New Guinea, Argentina, Brazil and Chile.

Description

''Araucaria'' are mainly large trees with a massive erect stem, reaching a height of . The horizontal, spreading branches grow in whorls and are covered with leathery or needle-like leaves. In some species, the leaves are narrow, awl-shaped and lanceolate, barely overlapping each other; in others they are broad and flat, and overlap broadly.

The trees are mostly dioecious, with male and female cones found on separate trees, though occasional individuals are monoecious or change sex with time. The female cones, usually high on the top of the tree, are globose, and vary in size among species from diameter. They contain 80–200 large edible seeds, similar to pine nuts, though larger. The male cones are smaller, long, and narrow to broad cylindrical, broad.

The genus is familiar to many people as the genus of the distinctive Chilean pine or monkey-puzzle tree (''Araucaria araucana''). The genus is named after the Spanish exonym ''Araucano'' ("from Arauco") applied to the Mapuche of south-central Chile and south-west Argentina, whose territory incorporates natural stands of this genus. The Mapuche people call it ', and consider it sacred. Some Mapuche living in the Andes name themselves Pehuenche ("people of the '") as they traditionally harvested the seeds extensively for food.

No distinct vernacular name exists for the genus. Many are called "pine", although they are only distantly related to true pines, in the genus ''Pinus''.

Distribution and paleoecology

Members of ''Araucaria'' are found in Argentina, Brazil, New Caledonia, Norfolk Island, Australia, New Guinea, Chile and Papua (Indonesia). Many if not all current populations are relicts, and of restricted distribution. They are found in forest and maquis shrubland, with an affinity for exposed sites. The earliest records of the genus date to the Middle Jurassic, represented by ''Araucaria mirabilis'' of Argentina, and ''Araucaria sphaerocarpa'' from England. Fossil records show that the genus also formerly occurred in the northern hemisphere until the end of the Cretaceous period.

By far the greatest diversity exists in New Caledonia, likely due to a relatively recent adaptive radiation, as all New Caledonian species are more closely related to each other than they are to other ''Araucaria''. Much of New Caledonia is composed of ultramafic rock with serpentine soils, with low levels of nutrients, but high levels of metals such as nickel. Consequently, its endemic ''Araucaria'' species are adapted to these conditions, and many species have been severely affected by nickel mining in New Caledonia and are now considered threatened or endangered, due to their habitat lying in prime areas for nickel mining activities.

Some evidence suggests that the long necks of sauropod dinosaurs may have evolved specifically to browse the foliage of tall trees, including those of ''Araucaria''. An analysis of modern ''Araucaria'' leaves found that they have a high energy content but are slow fermenting, making their ancestors a likely attractive target.

Classification and species list

There are four extant sections and two extinct sections in the genus, sometimes treated as separate genera.

Extant species

Genetic studies

Genetic studies indicate that the extant members of the genus can be subdivided into two large clades – the first consisting of the sections ''Araucaria'', ''Bunya'', and ''Intermedia''; and the second of the strongly monophyletic section ''Eutacta''. Sections ''Eutacta'' and ''Bunya'' are both the oldest taxa of the genus, with ''Eutacta'' possibly older.
::Taxa marked with are extinct.
* Section ''Araucaria''. Leaves broad; cones more than diameter; seed germination hypogeal. Syn. sect. ''Columbea''; sometimes includes ''Intermedia'' and ''Bunya''
** '' Araucaria angustifolia'' – Paraná pine (obsolete: Brazilian pine, candelabra tree); southern and southeastern Brazil, northeastern Argentina.
** ''Araucaria araucana'' – monkey-puzzle or ''pehuén'' (obsolete: Chile pine); central Chile & western Argentina.
** ''Araucaria nipponensis'' – Japan and Sakhalin (Upper Cretaceous)
* Section ''Bunya''. Contains only one living species. Produces recalcitrant seeds with hypogeal ( cryptocotylar) germination, though extinct species may have exhibited epigeal germination.
** ''Araucaria bidwillii'' – ''bunya-bunya''; Eastern Australia
* Section ''Intermedia''. Contains only one living species. Produces recalcitrant seeds
** ''Araucaria hunsteinii'' – ''klinki''; New Guinea
** ''Araucaria haastii'' - New Zealand (Cretaceous)
* Section ''Eutacta''. Leaves narrow, awl-like; cones less than diameter; seed germination epigeal
** '' Araucaria bernieri'' – New Caledonia
** ''Araucaria biramulata'' – New Caledonia
** ''Araucaria columnaris'' – Cook pine; New Caledonia
** ''Araucaria cunninghamii'' – Moreton Bay pine, hoop pine; Eastern Australia, New Guinea
** ''Araucaria goroensis'' – New Caledonia
** ''Araucaria heterophylla'' – Norfolk Island pine; Norfolk Island
** ''Araucaria humboldtensis'' – New Caledonia
** '' Araucaria laubenfelsii'' – New Caledonia
** '' Araucaria luxurians'' – New Caledonia
** '' Araucaria montana'' – New Caledonia
** '' Araucaria muelleri'' – New Caledonia
** ''Araucaria nemorosa'' – New Caledonia
** '' Araucaria rulei'' – New Caledonia
** '' Araucaria schmidii'' – New Caledonia
** ''Araucaria scopulorum'' – New Caledonia
** '' Araucaria subulata'' – New Caledonia
** '' Araucaria lignitici'' – (Paleogene) Yallourn, Victoria, Australia
**'' Araucaria famii –'' (Late Cretaceous) Vancouver Island, Canada.
* Section ''Yezonia''. Extinct. Contains only one species
** '' Araucaria vulgaris'' – Japan (Late Cretaceous)
* Section ''Perpendicula''. Extinct. Contains only one species
** ''Araucaria desmondii'' - New Zealand (Late Cretaceous)
* incertae sedis
** '' Araucaria beipiaoensis'' – Tiaojishan Formation, China (Middle Jurassic)
** '' Araucaria fibrosa'' – López de Bertodano Formation, Antarctica (Late Cretaceous)
** ''Araucaria marensii'' – La Meseta Formation, Antarctica & Santa Cruz Formation, Argentina''Araucaria marensii''
at Fossilworks.org
** ''Araucaria nihongii'' – Upper Yezo Group, Japan (Late Cretaceous)
** ''Araucaria taieriensis'' - New Zealand (Late Cretaceous)
**''Araucaria brownii'' - England (Middle Jurassic)
** ''Araucaria mirabilis'' – Patagonia (Middle Jurassic)
** ''Araucaria sphaerocarpa'' - England (Middle Jurassic)
''Araucaria bindrabunensis'' (previously classified under section ''Bunya'') has been transferred to the genus ''Araucarites''.

Uses

Some of the species are relatively common in cultivation because of their distinctive, formal symmetrical growth habit. Several species are economically important for timber production.

Food

The edible large seeds of ''A. araucana'', ''A. angustifolia'' and ''A. bidwillii'' — also known as ''Araucaria'' nuts, and often called, although improperly, ''pine nuts'' — are eaten as food, particularly among the Mapuche people of Chile and southwest Argentina, the Kaingang people in Southern Brazil and among Native Australians.
In South America ''Araucaria'' nuts or seeds are called ''piñas'' or ''piñones'' in Spanish and ''pinhões'' in Portuguese, like pine nuts in Europe.

Pharmacological activity

Pharmacological reports on genus Araucaria are anti-ulcer, antiviral, neuro-protective, anti-depressant and anti-coagulant.

See also

* '' Agathis'' (kauri)
* ''Wollemia''

References

External links

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Dioecious plants
Extant Triassic first appearances
Conifer genera